Earth Could Warm 11 Degrees By 2100: U.S. Climate Assessment

WASHINGTON, DC, May 6, 2014 (ENS) – By the year 2100, if greenhouse gas emissions stay on their current path, the global temperature could rise by more than 11 degrees Fahrenheit and sea levels could rise by up to four feet, affecting all Americans, finds the third U.S. National Climate Assessment released today.

From record heat and severe drought, torrential rains, storms and hurricanes, to sea level rise, states around the country are already feeling the effects of climate change, according to the assessment.

“Climate change is not a distant threat. It is already affecting the country and the economy … this is the loudest alarm bell to date,” said Dr. John Holdren, who heads the White House Office of Science and Technology Policy, on a conference call with reporters this morning.

“It is the most comprehensive scientific assessment ever generated of climate change and its impacts across every region of the United States and major sectors of the U.S. economy,” said Dr. Holdren.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and by experts, including federal agencies and a panel of the National Academy of Sciences.

Dr. Jerry Melillo, chair of the Federal Advisory Committee, told reporters on the call, “The key message is – climate change is happening now and affecting Americans on a day-to-day basis and in the longer term as well.”

“For decades we’ve been collecting the dots about climate change, now we’ve connected the dots,” said Melillo, a scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts.

“All Americans will find things that matter to them in this report. We are all bearing the cost of increases in heat, heavy downpours and storm surges,” Mellilo said.

Multiple lines of independent evidence point to a key message of the report, “The global warming of the past 50 years is primarily due to human activities.”

Coal-burning General James M. Gavin power plant on the Ohio River (Photo via Wikipedia)

“Natural drivers of climate cannot explain the recent observed warming,” the report states. “The majority of the warming at the global scale over the past 50 years can only be explained by the effects of human influences, especially the emissions from burning fossil fuels (coal, oil, and natural gas) and from deforestation.”

“The emissions from human influences that are affecting climate include heat-trapping gases such as carbon dioxide (CO2), methane, and nitrous oxide, and particles such as black carbon (soot), which has a warming influence, and sulfates, which have an overall cooling influence,” states the report.

How hot the climate gets in this century depends on the level of these emissions.

The lowest emissions pathway shown in the report assumes immediate and rapid reductions in emissions and would result in about 2.5°F of warming in this century.

But the highest pathway, roughly similar to a continuation of the current path of global emissions increases, is projected to lead to more than 8°F warming by 2100, with a high-end possibility of more than 11°F.

These temperatures are far above the two degree Celsius (3.6°F) temperature rise that world leaders agreed is safe at the 2009 UN climate summit in Copenhagen.

Sea levels along U.S. coastlines could rise as much as four feet by 2100, said Dr. Tom Karl, director of the National Oceanic and Atmospheric Administration’s National Climatic Data Center and a National Climate Assessment Federal Executive Team member.

“Back in 2000 we projected a rise in sea level of 10-17 inches,” said Karl. “That figure has been updated in this report. We now project that sea levels could rise between 12 and 48 inches by 2100.”

Arctic sea ice reached its maximum extent for the year on March 21, 2014 at 14.91 million square kilometers (5.76 million square miles), making it the fifth lowest maximum in the satellite record. (Image courtesy National Snow and Ice Data Center)

That sea level rise is due in part to losses from the ice shelves of Greenland and Antarctic, which are both declining, adding water to the oceans, the scientists said.

The report states, “Rising temperatures are reducing ice volume and surface extent on land, lakes, and sea. This loss of ice is expected to continue. … Confidence is very high that the Arctic Ocean is projected to become virtually ice-free in summer by mid-century.”

A National Climate Assessment is issued every four years by the U.S. Global Change Research Program.

This report divides the country into eight regions and shows that while the impacts of climate change vary from region to region, every region faces severe and costly impacts. There will be more competition for water in the arid Western states, more torrential rainfall in the Northeast and Midwest, and rising sea levels with giant storm surges along the Gulf and Atlantic coasts.

But the report is not intended to scare Americans, but to show the need to prepare communities for the coming changes and to explore the economic opportunities that exist to build resilience now.

Holdren told reporters on the call, “There are opportunities, a wide variety of cost-effective actions that we can take, but as the President’s Climate Action Plan says we need to get on with it.”

Outlining his Climate Action Plan at Georgetown University on June 25, 2013, President Obama said, “Science, accumulated and reviewed over decades, tells us that our planet is changing in ways that will have profound impacts on all of humankind. … Those who are already feeling the effects of climate change don’t have time to deny it – they’re busy dealing with it.”

John Podesta, counselor to the President, says the facts in this assessment are “actionable science.”

“Communities across the country at a regional level can understand what’s happening now, what the future is going to look like, and build resilence into their communities,” told reporters on the call.

“People get that climate change is happening, that it’s caused by burning fossil fuels, but they don’t know what to do with this information,” he said.

To help Americans understand what these facts mean, Podesta said government officials and scientists are going to “fan out across the country” and reach out to local and regional government officials.

For the first time, to ensure that American citizens, communities, businesses, and decision makers have easy access to scientific information about climate change impacts that are most relevant to them, the U.S. National Climate Assessment is being released in an interactive, mobile-device-friendly, digital format on www.globalchange.gov.

Today President Obama is hosting an event called Weather from the White House. He will conduct a round of interviews with national and local meteorologists from New York, San Francisco, Seattle, Chicago, and Columbia, South Carolina to discuss the meaning of the facts contained in this report and the impacts climate change is having on Americans.

Podesta said, “Hopefully, when the people understand the real world impacts happening right now, they’re going be more willing to take action.”

Environmental groups are urging immediate action in response to this report, particularly the the first nationwide limits on CO2 emissions from existing power plants expected from the Obama Administration shortly.

Kevin Kennedy, director of the World Resources Institute’s U.S. Climate initiative, said, “Next month, the Obama Administration is expected take a critical step forward by introducing the first-ever federal limits on carbon pollution from existing power plants. Power plants produce one-third of U.S. emissions and represent the greatest opportunity for the US to drive down its emissions. This will be a major – though not the only – step along the way to put America on course for a safer, low-carbon future.”

“Further delay will only accelerate climate change and raise the costs of addressing its impacts,” he said.

Eileen Claussen, president of the nonprofit Center for Climate and Energy Solutions, said, “Based on an exhaustive review of the latest scientific evidence, the report brings it home to Americans that we are not immune to threats posed by climate change to our infrastructure, water supplies, agriculture, ecosystems, and health.”

“Companies, communities, and individuals all need to better manage climate risks, both by reducing carbon emissions and by becoming more climate-resilient,” said Claussen. “Investments in mitigation will give our adaptation efforts a greater chance of success.”

“Fortunately, the Obama Administration is taking action – by setting standards for cleaner, more efficient cars and, within weeks, by issuing the first-ever nationwide limits on carbon pollution from our existing power plants. Cleaning up the air is a win-win: It can create thousands of jobs, expand energy efficiency and lower electric bills while improving public health,” said Beinecke. “That’s the climate legacy we can, and must, leave future generations.”

Facts from the third U.S. National Climate Assessment:

Climate Trends in America

• Temperature: “U.S. average temperature has increased by 1.3°F to 1.9°F since record keeping began in 1895; most of this increase has occurred since about 1970. The most recent decade was the Nation’s warmest on record. Temperatures in the United States are expected to continue to rise. Because human-induced warming is superimposed on a naturally varying climate, the temperature rise has not been, and will not be, uniform or smooth across the country or over time.” (NCA Highlights: Climate Trends)

• Extreme Weather: “There have been changes in some types of extreme weather events over the last several decades. Heat waves have become more frequent and intense, especially in the West. Cold waves have become less frequent and intense across the Nation. There have been regional trends in floods and droughts. Droughts in the Southwest and heat waves everywhere are projected to become more intense, and cold waves less intense everywhere.” (NCA Highlights: Climate Trends)

• Hurricanes: “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain. Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.” (NCA Highlights: Climate Trends)

• Severe Storms: “Winter storms have increased in frequency and intensity since the 1950s, and their tracks have shifted northward over the United States. Other trends in severe storms, including the intensity and frequency of tornadoes, hail, and damaging thunderstorm winds, are uncertain and are being studied intensively.” (NCA Highlights: Climate Trends)

• Precipitation: “Average U.S. precipitation has increased since 1900, but some areas have had increases greater than the national average, and some areas have had decreases. More winter and spring precipitation is projected for the northern United States, and less for the Southwest, over this century.” (NCA Highlights: Climate Trends)

• Heavy Downpours: “Heavy downpours are increasing nationally, especially over the last three to five decades. Largest increases are in the Midwest and Northeast. Increases in the frequency and intensity of extreme precipitation events are projected for all U.S. regions.” (NCA Highlights: Climate Trends)

• Frost-free Season: “The length of the frost-free season (and the corresponding growing season) has been increasing nationally since the 1980s, with the largest increases occurring in the western United States, affecting ecosystems and agriculture. Across the United States, the growing season is projected to continue to lengthen.” (NCA Highlights: Climate Trends)

• Ice Melt: “Rising temperatures are reducing ice volume and surface extent on land, lakes, and sea. This loss of ice is expected to continue. The Arctic Ocean is expected to become essentially ice free in summer before mid-century.” (NCA Highlights: Climate Trends)

• Sea Level: “Global sea level has risen by about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100.” (NCA Highlights: Climate Trends)

• Ocean Acidification: “The oceans are currently absorbing about a quarter of the carbon dioxide emitted to the atmosphere annually and are becoming more acidic as a result, leading to concerns about intensifying impacts on marine ecosystems.” (NCA Highlights: Climate Trends)

Climate-Change Impacts in Regions across America:

• Northeast – Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Delaware, Pennsylvania, Maryland, and District of Columbia: “Sixty-four million people are concentrated in the Northeast. The high-density urban coastal corridor from Washington, DC, north to Boston is one of the most developed environments in the world, containing a massive, complex, and long-standing network of supporting infrastructure. The Northeast also has a vital rural component.” Communities in the Northeast “are affected by heat waves, more extreme precipitation events, and coastal flooding due to sea level rise and storm surge.” (NCA Highlights: Northeast; NCA Highlights: Overview)

• Southeast and Caribbean – Virginia, W. Virginia, Kentucky, Tennessee, Georgia, Alabama, Arkansas, S. Carolina, N. Carolina, Mississippi, Florida, Louisiana, and the Caribbean Islands: The Southeast and Caribbean region “is home to more than 80 million people and some of the fastest-growing metropolitan areas… The Gulf and Atlantic coasts are major producers of seafood and home to seven major ports that are also vulnerable. The Southeast is a major energy producer of coal, crude oil, and natural gas.” “Decreased water availability, exacerbated by population growth and land-use change, causes increased competition for water in this region. There are also increased risks associated with extreme events such as hurricanes.” (NCA Highlights: Southeast & Caribbean; NCA Highlights: Overview)

• Great Plains – Wyoming, N. Dakota, S. Dakota, Montana, Nebraska, Kansas, Oklahoma, and Texas: The Great Plains region “experiences multiple climate and weather hazards, including floods, droughts, severe storms, tornadoes, hurricanes, and winter storms. In much of the Great Plains, too little precipitation falls to replace that needed by humans, plants, and animals. These variable conditions already stress communities and cause billions of dollars in damage. Climate change will add to both stress and costs.” “Rising temperatures lead to increased demand for water and energy and impacts on agricultural practices.” (NCA Highlights: Great Plains; NCA Highlights: Overview)

• Southwest – California, Nevada, Arizona, New Mexico, Utah, and Colorado: “The Southwest is the hottest and driest region in the United States. Climate changes pose challenges for an already parched region that is expected to get hotter and, in its southern half, significantly drier. Increased heat and changes to rain and snowpack will send ripple effects throughout the region… and its critical agriculture sector.” “Drought and increased warming foster wildfires and increased competition for scarce water resources for people and ecosystems.” (NCA Highlights: Southwest; NCA Highlights: Overview)

• Northwest – Idaho, Oregon, and Washington: “The Northwest’s economy, infrastructure, natural systems, public health, and agriculture sectors all face important climate change related risks. Impacts on infrastructure, natural systems, human health, and economic sectors, combined with issues of social and ecological vulnerability, will unfold quite differently in largely natural areas, like the Cascade Range, than in urban areas like Seattle and Portland or among the region’s many Native American Tribes.” “Changes in the timing of streamflow related to earlier snowmelt reduce the supply of water in summer, causing far-reaching ecological and socioeconomic consequences.” (NCA Highlights: Northwest; NCA Highlights: Overview)

• Alaska: “Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the United States…The state’s largest industries, energy production, mining, and fishing – are all affected by climate change.” “Rapidly receding summer sea ice, shrinking glaciers, and thawing permafrost cause damage to infrastructure and major changes to ecosystems. Impacts on Alaska Native communities increase.” (NCA Highlights: Alaska; NCA Highlights: Overview)

• Hawaii and Pacific Islands: The U.S. Pacific Islands region “includes more than 2,000 islands spanning millions of square miles of ocean. Rising air and ocean temperatures, shifting rainfall patterns, changing frequencies and intensities of storms and drought, decreasing streamflows, rising sea levels, and changing ocean chemistry will threaten the sustainability of globally important and diverse ecosystems…as well as local communities, livelihoods, and cultures.” “Increasingly constrained freshwater supplies, coupled with increased temperatures, stress both people and ecosystems and decrease food and water security.” (NCA Highlights: Hawaii and the Pacific Islands; NCA Highlights: Overview)

• Coasts: “More than 50% of Americans – 164 million people – live in coastal counties, with 1.2 million added each year… Humans have heavily altered the coastal environment through development, changes in land use, and overexploitation of resources. Now, the changing climate is imposing additional stresses…” “Coastal lifelines, such as water supply infrastructure and evacuation routes are increasingly vulnerable to higher sea levels and storm surges, inland flooding, and other climate-related changes.” (NCA Highlights: Coasts; NCA Highlights: Overview)

Climate-Change Impacts on Key Sectors of Society and the U.S. Economy

• Health: “Climate change threatens human health and well-being in many ways, including through impacts from increased extreme weather events, wildfire, decreased air quality, threats to mental health, and illnesses transmitted by food, water, and disease carriers such as mosquitoes and ticks. Some of these health impacts are already underway in the United States. Climate change will, absent other changes, amplify some of the existing health threats the Nation now faces. Certain people and communities are especially vulnerable, including children, the elderly, the sick, the poor, and some communities of color. Public health actions, especially preparedness and prevention, can do much to protect people from some of the impacts of climate change. Early action provides the largest health benefits.” (NCA Highlights: Human Health)

• Transportation: “The impacts from sea level rise and storm surge, extreme weather events, higher temperatures and heat waves, precipitation changes, Arctic warming, and other climatic conditions are affecting the reliability and capacity of the U.S. transportation system in many ways. Sea level rise, coupled with storm surge, will continue to increase the risk of major coastal impacts on transportation infrastructure, including both temporary and permanent flooding of airports, ports and harbors, roads, rail lines, tunnels, and bridges. Extreme weather events currently disrupt transportation networks in all areas of the country; projections indicate that such disruptions will increase. Climate change impacts will increase the total costs to the Nation’s transportation systems and their users, but these impacts can be reduced through rerouting, mode change, and a wide range of adaptive actions.” (NCA Highlights: Transportation)

• Energy: “Extreme weather events are affecting energy production and delivery facilities, causing supply disruptions of varying lengths and magnitudes and affecting other infrastructure that depends on energy supply. The frequency and intensity of certain types of extreme weather events are expected to change. Higher summer temperatures will increase electricity use, causing higher summer peak loads, while warmer winters will decrease energy demands for heating. Net electricity use is projected to increase. Changes in water availability, both episodic and long-lasting, will constrain different forms of energy production. In the longer term, sea level rise, extreme storm surge events, and high tides will affect coastal facilities and infrastructure on which many energy systems, markets, and consumers depend. As new investments in energy technologies occur, future energy systems will differ from today’s in uncertain ways. Depending on the character of changes in the energy mix, climate change will introduce new risks as well as new opportunities.” (NCA Highlights: Energy Supply and Use)

• Water: “Climate change affects water demand and the ways water is used within and across regions and economic sectors. The Southwest, Great Plains, and Southeast are particularly vulnerable to changes in water supply and demand. Changes in precipitation and runoff, combined with changes in consumption and withdrawal, have reduced surface and groundwater supplies in many areas. These trends are expected to continue, increasing the likelihood of water shortages for many uses. Increasing flooding risk affects human safety and health, property, infrastructure, economies, and ecology in many basins across the United States… Increasing resilience and enhancing adaptive capacity provide opportunities to strengthen water resources management and plan for climate-change impacts.” (NCA Highlights: Water)

• Agriculture: “Climate disruptions to agriculture have been increasing and are projected to become more severe over this century. Some areas are already experiencing climate-related disruptions, particularly due to extreme weather events. While some U.S. regions and some types of agricultural production will be relatively resilient to climate change over the next 25 years or so, others will increasingly suffer from stresses due to extreme heat, drought, disease, and heavy downpours. From mid-century on, climate change is projected to have more negative impacts on crops and livestock across the country – a trend that could diminish the security of our food supply… Climate change effects on agriculture will have consequences for food security, both in the U.S. and globally, through changes in crop yields and food prices and effects on food processing, storage, transportation, and retailing. Adaptation measures can help delay and reduce some of these impacts.” (NCA Highlights: Agriculture)

• Ecosystems: “Ecosystems and the benefits they provide to society are being affected by climate change. The capacity of ecosystems to buffer the impacts of extreme events like fires, floods, and severe storms is being overwhelmed. Climate change impacts on biodiversity are already being observed in alteration of the timing of critical biological events such as spring bud burst, and substantial range shifts of many species. In the longer term, there is an increased risk of species extinction. Events such as droughts, floods, wildfires, and pest outbreaks associated with climate change (for example, bark beetles in the West) are already disrupting ecosystems. These changes limit the capacity of ecosystems, such as forests, barrier beaches, and wetlands, to continue to play important roles in reducing the impacts of extreme events on infrastructure, human communities, and other valued resources… Whole-system management is often more effective than focusing on one species at a time, and can help reduce the harm to wildlife, natural assets, and human well-being that climate disruption might cause.” (NCA Highlights: Ecosystems)

• Oceans: “Ocean waters are becoming warmer and more acidic, broadly affecting ocean circulation, chemistry, ecosystems, and marine life. More acidic waters inhibit the formation of shells, skeletons, and coral reefs. Warmer waters harm coral reefs and alter the distribution, abundance, and productivity of many marine species. The rising temperature and changing chemistry of ocean water combine with other stresses, such as overfishing and coastal and marine pollution, to alter marine-based food production and harm fishing communities… In response to observed and projected climate impacts, some existing ocean policies, practices, and management efforts are incorporating climate change impacts. These initiatives can serve as models for other efforts and ultimately enable people and communities to adapt to changing ocean conditions.” (NCA Highlights: Oceans)